···232232from any file, without any `mkIf`/`mkMerge` cluttering. The logic for
233233determining if the class takes effect is defined at a single place.
234234235235+> Example from @Doc-Steve (author of [Dendritic Design Guide](https://github.com/Doc-Steve/dendritic-design-with-flake-parts))
236236+235237```nix
236238# Aspects use the `persys` class without any conditional. And guard guarantees
237239# settings are applied **only** when impermanence module has been imported.